Synergistic photocatalytic and Fenton-like degradation of organic contaminants using peroxymonosulfate activated by CoFe₂O₄@g-C₃N₄ composite

The integration of two different advanced oxidation processes can not only avoid their individual shortcomings but also utilize the synergistic effects between them. Herein, CoFe₂O₄ modified g-C₃N₄ composite (CoFe₂O₄@g-C₃N₄) was synthesized and used for building a novel coupled system, in which two processes of visible light-activated photocatalysis and sulfate radical-based Fenton-like oxidation have been combined together to provide a synergistic reaction path for the removal of rhodamine B. The coupled system exhibited a drastically enhanced catalytic efficiency compared with the photocatalytic or Fenton-like process alone. It also showed a significantly enhanced catalytic activity compared with g-C₃N₄, CoFe₂O₄ or their simple mixture. The improved catalytic performance can be ascribed to the efficient separation of photogenerated carriers as well as more available catalytic reactive sites for peroxymonosulfate (PMS) activation due to the synergistic effects between the photocatalytic and Fenton-like processes. In 30 min, 96% RhB was degraded using PMS activated by a CoFe₂O₄@g-C₃N₄ composite with 3% CoFe₂O₄ loading under visible light irradiation, and the synergistic index in such system reached as high as 3.07. Such system can be used at a wide pH range of 3.0–10.0. The composite also showed good stability for its practical applications.